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Information for Gemini parents

Thank you for being part of the Gemini study for the past 15 years. You and your twins have helped to make Gemini an internationally renowned study that has led to important discoveries about children’s health and development. Gemini is now considered a key resource for understanding how children’s eating patterns develop.

Adolescence is an important time during which eating habits often change a lot. As children mature into teenagers, they gain independence to make more of their own decisions about what and how much to eat. But compared to children, adolescents tend to eat fewer fruits and vegetables, and more foods that are high in fat, salt and/or sugar (such as crisps, chocolate, sweets, and fast foods). Researchers don’t know much about why this happens. The aim of the next phase of Gemini is to find out what adolescents eat and why. This will allow us to work out how best to support teenagers to eat healthily.

If you missed any previous Gemini questionnaires, your twins can still participate in this next phase. Your information is always valuable to the study. We would like to encourage all Gemini families who started the study in 2007-8 to take part now.

What will the current study involve for me?

We would like to find out what your twins eat and drink by asking them directly. To do this we need to ask you to agree (consent) to 2 things: (i) allowing us to collect your twins’ contact details (email address and/or phone number); and (ii) agreeing, in principle, for your twins to participate in the study. We have provided information (see webpage 'Study information for Twins' about this study for you to share with your twins if you are happy for them to take part.

If you are happy for us to contact your twins (provide 'consent') please click pn the link below. Or select 'Consent to my twins taking part' in the top right hand panel of this page.

What does the current study involve?

Once we have your consent, we will ask your twins to agree (consent) to take part and agree to give us their contact details (email address and/or phone number) so we can send them a link to their own unique online food and drink survey, using software called Intake24 ( We will ask them to complete the online survey on 3 separate days (1 weekend day and 2 weekdays); each time they complete the survey they will be asked to report everything they ate and drank on the previous day. We will send them a link to each of the 3 surveys by text or email, along with reminders.


Intake24 was developed especially for teenagers and is completed by 1000s of people each year who take part in the UK National Diet and Nutrition Survey - the longest running survey of food and drink intakes in the UK. It shouldn’t take too long for your twins to complete (15-20 minutes) and they can complete it at their own leisure. If possible, it is best for your children to complete each survey all in one go (i.e. a single session). If this is not possible, or the session is interrupted, they can log in again later, but they will need to complete it before midnight the same day or their information will be lost. 

Rewards for taking part

The Gemini team would like to say a big thank you for taking part in our recent studies. The research would not be possible without your continued time and support. To say thank your twins for taking part, we will send them (by email) a £10 Love2shop voucher each ( The voucher will be sent to each twin once they have completed the surveys for all 3 days. 

What are the possible benefits or disadvantages of taking part?

Several Gemini families have contacted us to tell us how much they have enjoyed being part of a study that is making important strides in improving the health and development of children. Many families have also told us that the questions we have asked previously gave them the opportunity to reflect on their family life, which they valued enormously. We have also had positive feedback from families about the yearly updates on the study that we provide through the annual newsletter.


Some teenagers may feel uncomfortable reporting everything they have eaten and drunk recently. However, your child will be reassured that the information they give us will remain confidential and anonymous. Previous research with teenagers about eating and drinking has not shown any harm. However, if your child feels upset or uncomfortable, they can stop at any time. If you are concerned your child may have an eating disorder, the charity Beat Eating Disorders provides information and help online: If you are very worried about your child’s eating, talk to your GP.

Do my twins have to take part?

It is up to you and your twins to decide whether they take part. Your children can withdraw at any time without giving a reason and without it affecting any benefits that you are entitled to. If your twins decide to withdraw, you and your family can still be part of the Gemini study.

What will happen to the results of the research project?

As we have done every year since the study began, we will send you an annual newsletter informing you about the progress and results of the study. We will also include summaries of the findings on the Gemini website (, via the Gemini Twitter account (@GeminiResearch), the Gemini Facebook page (Gemini - Health and Development in Twins) and the Gemini Instagram page (@geminiresearch). We will also present results at conferences and publish them in scientific journals.

When will I be contacted again?

We would like to contact you and your twins again over the next five years. You do not have to let us know now whether or not you would like to continue to participate. We will confirm this with you the next time we contact you. 

Will our participation in this project be kept confidential?

Yes. All the information that we collect about your twins during the research will be kept strictly confidential. The information provided will be stored in a pseudoanonymised format using your participant ID numbers (separate from your name and contact details), on a secure server at UCL. The food and drink information entered by your twins will go directly to the Intake24 databases, but this will use a new participant ID number that is separate to the ID numbers we store at UCL, therefore it will not be possible to identify you or your twins from the Intake24 database. Once the data is returned to UCL for storage on the secure server, a member of the Gemini team will link the information back to your twins’ original participant ID numbers and previously collected data. It will not be possible to identify any individual (parent or child) from the data, or in any ensuing reports or publications.


Confidentiality will be respected subject to legal constraints and professional guidelines.  For more information please read our Data Protection Privacy Policy.

Who is organising and funding the research? 

The research is organised by the Gemini research team at UCL, led by Dr Clare Llewellyn, in collaboration with the University of Cambridge Medical Research Council Epidemiology Unit.


To satisfy research council research, we are obligated to make the pseudoanonymised data available for future research should other researchers request it.


What if something goes wrong? 

If you have concerns about this research, please contact Dr Alice Kininmonth []. Should you wish to take your matter further you can contact the Chair of the UCL Research Ethics Committee ( 

Contact information

Thank you for reading this information about the study and for considering taking part in the next phase of Gemini research.If you have any queries about the study, please contact Dr Kininmonth; 020 3108 9696; Dr Kininmonth will reply to your email as soon as possible Monday to Friday. Please note that telephone enquiries may take longer to reply as staff members are not always at the desk due to research activities. If the call is not answered straight away, please leave a message and we will respond as soon as possible.

All proposals for research using people are reviewed by an ethics committee before they can proceed. This study has been approved by the UCL Research Ethics Committee (Project ID Number: 1624/004)


Please click here to download a copy of this information about the study and keep it for future reference. 

Thank you for reading this information

The Gemini Team

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